بررسی آت اکولوژی ‭Astragalus cyclophyllon G.Beek ‬در استان اصفهان

The Autecology is a branch of ecology that studies the relationships between of organisms and their environment. Nowadays offspring of important range plants are declined because of genetic erosion and grazing pressure. The plant genetic erosion is unknown due to special contortion of plant associations and absences of sufficient data. Study of native plant that adapted to Iran environment during past years in order to range reclamation is necessary. Both autecology and synecology is studied in Iran; however a lot of endemic range plants (as Astragalus cyclophyllon, which is important range species) are unknown. A. cyclophyllon is a forage, palatable and soil conservation plant that there isn't sufficient information about it. The auto ecology of A. cyclophyllon has been studied from 2003 to 2006. The method of research is as standard method which refers to botanical, phonology and ecology. The relationship between A. cyclophyllon and land form (slope, direction and height), soil, density, sub dominant species, canopy cover percent, root distribution, phytomass and under ground mass were studied. Semi steppic regions were selected as study units for A. cyclophyllon map. Phonological studies were surveyed in different date for Semirom and Chadegan. Density and canopy cover percent were determined by plot method. Root system distribution and number of up ground organs were determined on 5 individual plants. There was A. cyclophyllon in semi steppic regions in different geographical direction from 1900 meter to 2600 meter height. The sub dominant species with A. cyclophyllon were Bromus tomentellus, Eurotia ceratoides, Scariola orientalis and Stipa barbata. A. cyclophyllon was being emergence from early of February. Forb growth was ended in early days of May. Florescent emergence was from end of April to early of June, and Flower stage, seed maturity and seed falling were from early of June to early of July. Plant density of this species in Semirom, Zayanderood dam research station and watershed station are 4000- 8000, 678 and 1666 per hectare, respectively. Canopy cover percent in Chadegan and Semirom are 0.47-1.94 and 2.35-6.1, respectively. Root depth in Chadegan and Semirom are 80-120 centimeters. Plant frequency in Chadegan and Semirom are 10.00-31.25 and 32-34.37 percent, respectively. The origin of these planes is flood material of mountains. The origin of these land soils is calcareous (lime) material that organic material rate of them is less than 1%. In additional A. cyclophyllon growth in plane land, pediment land and calcareous (lime) soils that texture of them is light to heavy. Plant dispersion of A. cyclophyllon in Isfahan province is Semirom, Chadegan, Ferridonshahr, Khansar, Freidan and Golpaiegan. Maximum height of A. cyclophyllon is 70 centimeters and diameter is 75 centimeter. Maximum number of florescent per plant is 60. Life duration of A. cyclophyllon is about 120 days. Propagation method of A. cyclophyllon is seed method. Key word: Allelopathy, Autecology, Phenology, Isfahan Province, Astragalus cyclophyllon.